5D MkII, 7D or 1D MkIV

I'm a long time Nikon user that has decided to move to Canon. Reasons? I have a few but that's not important. What is important is that I have never used Canon and I would like to have your opinions on the Canon following models: the cameras 7D, 5D MkII, or 1D MkIV.

The majority of my work is portrait work, senior pictures, head shots, etc. but I do a fair amount of event photography, grab and grin work as well as print on site work.